相关论文: How well can we measure supermassive black hole sp…

In this paper, we investigate the quality of constraining the spin of the massive black hole (MBH) at the Galactic center (GC) by using full general relativistic simulations of the motion of a surrounding star. We obtain the dependence…

Generic extensions of the standard model predict the existence of ultralight bosonic degrees of freedom. Several ongoing experiments are aimed at detecting these particles or constraining their mass range. Here we show that massive vector…

We have embarked in an HST program to determine the masses of black holes in spiral galaxies directly by measuring the line emission arising from an extended accretion disk. For each of the galaxies in our sample we have measured the…

Infrared, optical and ultraviolet spectropolarimetric observations have proven to be ideal tools for the study of the hidden nuclei of type-2 active galactic nuclei (AGN) and for constraining the composition and morphology of the sub-parsec…

We revisit the problem of predicting the spin magnitude and direction of the black hole resulting from the merger of two black holes with arbitrary masses and spins inspiralling in quasi-circular orbits. We do this by analyzing a catalog of…

1E 1740.7-2942 is one of the strongest hard X-ray emitters in the Galactic Centre region, believed to be a black hole in a high-mass X-ray binary system. Although extensively studied in X-rays, many aspects about the underlying nature of…

We report on the iron K-alpha line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM…

X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general relativistic approach to model this irradiation for different…

The X-ray spectra of active galactic nuclei (AGN) unveil properties of matter around the super massive black hole (SMBH). We investigate the X-ray spectra of AGN focusing on Compton reflection and fluorescence, important processes of…

Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe K$\alpha$ emission line and Compton-reflection…

The spin-orbit misalignment of stellar-mass black hole (sBH) binaries provide important constraints on the formation channels of merging sBHs. Here, we study the role of secular spin-orbit resonance in the evolution of a sBH binary…

The X-ray properties of Active Galactic Nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some of the largest known accretion rates without…

The black-hole spin parameter, $a_*$, was measured to be close to its maximum value of 1 in many accreting X-ray binaries. In particular, $a_*\gtrsim 0.9$ was found in a number of studies of LMC X-1. These measurements were claimed to take…

Variability of active galactic nuclei is not well understood. One possible explanation is existence of supermassive binary black holes (SMBBH) in their centres. It is expected that major mergers are common in the Universe. It is expected…

Studies of black hole spin and other parameters as a function of redshift provide information about the physical state and merger and accretion histories of the systems. One way that black hole spin may be estimated is through observations…

The recently released images of the supermassive black holes in the M87 galaxy and the galaxy of our own make probing black hole spacetimes and testing general relativity (GR) possible. The violation of equatorial reflection symmetry of…

The fast variability of energetic TeV photons from the center of M87 has been detected, offering a new clue to estimate spins of supermassive black holes (SMBHs). We extend the study of Wang et al. (2008) by including all of general…

The spin state of holes bound to Mn acceptors in GaMnAs is investigated by optical spectroscopy. Concentrations of Mn from 10^17 to 10^19 cm^-3 were studied as a function of magnetic field and temperature. The photoluminescence from…

With one exception, previous analyses of the measurement accuracy of gravitational wave experiments for comparable-mass binary systems have neglected either spin-precession effects or subdominant harmonics and amplitude modulations. Here we…

In active galactic nuclei, X-ray illumination of the accretion disk around a supermassive black hole (SMBH) results in the production of the K$\alpha$ fluorescent line of iron, which provides insights into accretion physics and SMBH spins.…